class_docstr: GRU cell for matrix, similar to the official code.
  Please refer to section 3.4 of the paper for the formula.
code: def __init__(self, in_feats, out_feats):
      super().__init__()
      self.update = MatGRUGate(in_feats, out_feats, torch.nn.Sigmoid())
  
      self.reset = MatGRUGate(in_feats, out_feats, torch.nn.Sigmoid())
  
      self.htilda = MatGRUGate(in_feats, out_feats, torch.nn.Tanh())
  
imports: import torch
  import torch.nn
  from dgl.nn.pytorch import GraphConv
  from torch.nn import init
  from torch.nn.parameter import Parameter
label_desc: Use image node_id 1 to create a new MatGRUCell object from inherited base classes: torch.nn with example: obj = MatGRUCell(in_feats, out_feats)